Collaborative research: Controls affecting greenhouse gas fluxes in restored and natural tidal wetlands

1133074 (Jaffe)。在河口湿地地区，一氧化二氮（N2O）、甲烷（CH4）和二氧化碳（CO2）的温室气体（GHG）排放量在很大程度上是未知的。人工湿地是净辐射汇的概念尚未在沿海湿地得到证实，许多支持这一假设的研究没有考虑N2O通量。河口湿地、大气和邻近河流之间的氮和碳物种通量将沿着水期、盐度和缓解梯度进行测量，并按比例缩放到生态系统水平。涡旋相关方差技术将是用来约束CO2和CH4通量估计的主要方法。通量室和地下溶解的CH4、N2O和无机碳测量将结合这些通量的建模/缩放，以确定N2O通量，并通过比较两种技术的CO2和CH4通量来验证该技术的准确性。通过潮汐流从选定的沼泽中流失的溶解有机碳、溶解无机碳和溶解氮的净损失也将在这些沼泽的入口点进行监测。同时测量芦苇（芦苇属c3植物）和米草属（米草属c4植物）的光合作用，将解释这两个物种之间的二氧化碳交换。这种气体交换由生物物理、水文和水化学驱动因素驱动。咸淡海岸湿地的碳固存与来自同一系统的CH4和N2O排放之间的平衡尚不清楚。因此，在单个植物和生态系统水平上监测和模拟这些驱动因素对总体温室气体交换的影响，将有助于评估这些控制因素，并将城市潮汐湿地的温室气体通量扩大到生态系统水平。将采用自下而上的方法（通过测量和pi开发的基于过程的模型）和自上而下的方法（通过涡流通量测量）相结合的方法来解决生物圈-大气温室气体交换的不同驱动因素，并将其扩展到生态系统和区域水平。本研究将有助于加深对城市潮汐沼泽滨海湿地温室气体动态的认识。这些新的见解将与梅多兰兹环境中心的许多游客分享，其中包括每年参加各种关于城市河口的研讨会和教育活动的约15,000名学童。这项研究还将包括为路易斯·斯托克斯少数民族参与联盟（LSAMP）的一名学生提供资金，该学生将被雇用进行暑期实习，以协助研究生进行实地数据收集和外展活动。此外，自2003年以来，梅多兰环境研究所（MERI）与政府机构和大学合作，每四年举办一次梅多兰研讨会，聚集了200多名研究科学家、学生和专业人士，讨论和解决城市河口的环境问题。该项目还将培养两名研究生，一名在罗格斯大学，另一名在普林斯顿大学。这项研究的结果将通过会议报告和同行评议的期刊文章传播。实验设置和生成的数据将由两个pi使用，以增加学生在研究生和本科生实验中的实践经验。这项研究将产生一个丰富的数据集，由MERI维护，这将对温室气体建模科学界非常有价值

1133074 (Jaffe). Greenhouse gas (GHG) emissions of nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) are largely unknown for estuarine wetland areas. The notion that constructed wetlands are net radiative sinks has not been verified for coastal wetlands and many of the studies informing this hypothesis have not considered N2O fluxes. Fluxes of nitrogen and carbon species between estuarine wetlands, the atmosphere, and an adjacent river will be measured along a hydroperiod-, salinity-, and mitigation gradient and scaled to the ecosystem level. The eddy covariance technique will be the principal method used to constrain estimates of the CO2 and CH4 fluxes. Flux chamber and subsurface dissolved CH4, N2O, and inorganic carbon measurements combined with modeling/scaling of these fluxes will be used to determine the N2O fluxes and verify the accuracy of this technique by comparing CO2 and CH4 fluxes from both techniques. Net losses of dissolved organic carbon, dissolved inorganic carbon, and dissolved nitrogen from selected marshes via tidal flow will also be monitored at point inlets to these marshes. Concurrent photosynthesis measurements of Phragmites australis, a C3-plant, and Spartina spp, C4-plants, will account for the CO2 exchange by these species. This gas-exchange is driven by biophysical, hydrological and hydrochemical drivers. The balance between carbon sequestration in brackish coastal wetlands and CH4 and N2O emissions from the same systems remains unclear. Thus, monitoring and modeling the effects of these drivers on overall greenhouse gas exchange, at the individual plant and ecosystem-level, will help assess these controls and scale GHG fluxes in urban tidal wetlands to the ecosystem level. A combination of bottom-up approaches, via measurements and process-based models developed by the PIs, and top-down approaches via eddy flux measurements will be used to tackle the different drivers of biosphere-atmosphere GHG exchange and enable scaling to ecosystem and regional levels. This research will enhance our understanding of coastal wetland GHG dynamics in urban tidal marshes. These new insights will be shared with the many visitors of the Meadowlands Environmental Center, including ca. 15,000 schoolchildren who participate in a wide range of workshops and educational activities about urban estuaries each year. This research will also include funding for a Louis Stokes Alliances for Minority Participation (LSAMP) student to be hired for a summer internship to assist the graduate students in field data collection and outreach activities. In addition, every four years since 2003, Meadowlands Environmental Research Institute (MERI) has collaborated with government agencies and universities to sponsor the Meadowlands Symposium, a gathering of over 200 research scientists, students, and professionals, to discuss and address environmental issues of urban estuaries. The project will also train two graduate students, one at Rutgers University and one at Princeton University. Results from this research will be disseminated via conference presentations and peer-reviewed journal articles. The experimental setup and data generated will be used by both PIs to augment hands-on experiences for students in their graduate and undergraduate experiments. This research will yield a rich data set, maintained by MERI, that will be highly valuable to the green-house-gas modeling scientific community